<p>To extend or customize Bitrix Framework kernel and modules to your website,
use the conventional system <a href="http://www.bitrixsoft.com/help/source/main/help/en/developer/general/technology/events.php.html">event
handler technology</a>. </p>

<p>In most cases, this technology is sufficient to fit the Bitrix Framework
platform to any web project. However, if more substantial changes need to be
made to implement features required by the website specifications and those
changes simply cannot be done using existing event handlers, you may ask
technical support to implement the required events.</p> 

<p>Changing the Bitrix Framework kernel is strictly prohibited because any
system update downloaded and installed using the SiteUpdate technology will
overwrite the kernel irreversibly. Of course, you can update the kernel manually
by checking the source code line by line and adding new lines - but doing so
will be a calamity for you or system administrator. The rule is simple: resort
to event handlers, or create a new module to implement any feature that cannot
be done otherwise. </p>


<ul>
  <li>Check that the website specifications include the description of event
    handlers that are used in the project. Such description should be kept
    up-to-date whenever any change is made to the existing event handlers, or a
    new event handler is added.</li>
</ul>
